Jolt control systems are known in which the torque delivered by the internal combustion engine is reduced throughout the shift operation. For example, in British Pat. No. 929,621, a system is described in which the upshift signals activate monostable multivibrators which cause a temporary closing of the throttle valve.
German Pat. No. 10 80 415 describes a jolt control system in which a switch is operated when a shaft has predetermined angular positions. Operation of the switch activates a relay and a solenoid controlling a linkage which determines the opening of the throttle valve or the ignition timing.
U.S. Pat. No. 3,354,744 describes apparatus in which a shift command operates a pawl which blocks the fuel supply from the internal combustion engine during the shift operation until synchronous operation of the different parts of the transmission has been reestablished.
In the system described in DE-AS 16 26 427, the speed of the internal combustion engine is decreased during the shifting operation by a change in the ignition timing. A delay circuit is supplied which becomes operative at the start of the shift operation.
In French Pat. No. 1,524,354 a timing circuit interrupts the fuel injection for a predetermined time during the shift operation.
Similarly, in DE-AS 21 09 620, a circuit interrupting fuel injection is activated after a time delay following the activation of the solenoid valve effecting the shift.
Finally, in the system disclosed in DE-AS 21 63 979, the upshift signal applied to the automatic transmission is differentiated and the so-differentiated signal is applied to a computer which decreases the width of the pulse controlling the injection time.
These known arrangements for decreasing the engine torque during gear shifting have the common disadvantage that the fuel supply is decreased or the timing changed either throughout the whole shift operation or, by means of a timing circuit, for a predetermined time interval. None of these systems consider that the actual time interval should vary as a function of a number of different parameters as, for example, the particular gears involved in the shift, the actual engine speeds, the load on the engine, etc. Applying the jolt control during a predetermined time interval therefore does not result in an actual optimum jolt reduction.